The present invention, in some embodiments thereof, relates to coloring of three-dimensional printed objects and, more particularly, but not exclusively, to a method of ensuring uniformity of individual colors in a multi-colored object.
In three-dimensional printing, an object is formed by selective deposition of layers using a 3D printing device. In many cases a multi-colored object is required, and art is known for producing multi-colored objects from a 3D printer. In general, transparent or white material is used to make the object and different faces of the object face different directions. The overall perceived color is contributed to by the surface layers and the layers immediately underneath and this gives rise to the problem, that at junctions between faces, or in thin parts of the structure where opposites faces are close together, colors from other regions may interfere to give a non-uniform color effect. Likewise radiation, such as UV radiation that may be used to cure the colors, may not radiate evenly over differentially-facing surfaces, or may be blocked or shaded from reaching some parts of the 3D objects.
Color uniformity has been dealt with in standard two-dimensional printing, but the issue of angles and adjoining faces does not apply. Furthermore, although a printing substrate may sometimes be transparent, if printing on opposite faces, an opaque substrate is used.
Color uniformity has also been dealt with in conventional manufacture. However, in conventional manufacture a prototype is built and then coloration can be corrected if needed. In three-dimensional printing the initial prototype is the final object and thus no such color correction option is typically available.